Llanfechan is a small church settlement in the community of Treflys, consisting of a church and a farm, and the surrounding area, it is beside the A483 on the north side of the Irfon Valley near Cilmeri, about 7 kilometers (4.3 mi) west of Builth Wells, Powys, Wales.

The Imperial Gazetteer of England and Wales (1870–72) describes the settlement as follows: LLANAFAN-FECHAN, or LLANFECHAN, a parish in Builth district, Brecon; on the river Irvon ...

[4] In 1881, agriculture dominated male employment (64% of 39) and apart from a schoolmaster all the rest had manual jobs of various kinds.

The church is of typical medieval size and plan and this probably reflects the footprint of its predecessor.

It is not known where or when he was a bishop, but the name by which he was referred suggests his diocese was around Builth in Brycheiniog with his seat at Llanafan Fawr.